Modified polymers that are modified with compounds having nitrone groups (nitrone compounds) have been known conventionally as polymers contained in rubber compositions for use in tires and the like.
For example, claim 1 of Patent Document 1 discloses “a rubber composition comprising from 10 to 120 parts by weight of silica per 100 parts by weight of diene-based rubber containing from 5 to 100% by weight of modified butadiene rubber, the modified butadiene rubber being obtained by modifying a butadiene rubber having a cis-content of 90% or greater with a nitrone compound having a nitrogen-containing heterocycle in a molecule.” Patent Document 1 discloses that heat build-up is reduced by modification using a nitrone compound.